Production of spinnable polyamides exhibiting a high regularity and a high dyeability by acidic dyestuffs

ABSTRACT

OR (R1, R2, R3)-N-R4-COO-, WHERE THE SUBSTITUENTS INDICATED BY THE R&#39;&#39;S CAN BE SELECTED WITHIN A WIDE, BUT NEVERTHELESS STRICTLY DEFINED RANGE.   R-NH-R&#39;&#39;   A METHOD IS DISCLOSED FOR IMPROVING THE DYEABILITY OF POLYMIDE FIBRES BY ACIDIC DYES, SAID METHOD COMPRISING AS AN ESSENTIAL STEP THE ADOPTION OF A NITROGENOUS COMPOUND, WHICH CAN BE BROADLY DEFINED AS BELONGING TO THE CLASS OF BETAINES OR BETAINE-LIKE COMPOUNDS. MANY EXAMPLES ARE GIVEN, WHICH SHOW THE CRITICALLY OF THE SELECTION OF THE SUBSTITUENTS IN THE GENERAL FORMULA

United States Patent O US. Cl. 26078 R Claims ABSTRACT OF THE DISCLOSUREA method is disclosed for improving the dyeability of polyamide fibresby acidic dyes, said method comprising as an essential step the adoptionof a nitrogenous compound, which can be broadly defined as belonging tothe class of betaines or betaine-like compounds. Many examples aregiven, which show the criticality of the selection of the substituentsin the general formula or (R R R )N-R COO, where the substituentsindicated by the Rs can be selected within a wide, but neverthelessstrictly defined range.

This invention relates generally to the production of syntheticpolyamide-based materials, more particularly polyamides to be used inthe production of fibres, threads and yarns and having a high tinctorialuniformity along with a high degree of dyeability with acidic dyestuffs.

The importance of a good dyeability is already known with respect to theacidic dyeing materials, for textile materials such as, moreparticularly, fibres and yarns employed in the manufacture of fabricsintended for making articles of clothing and the like. Obviously, a highdegree of afiinity towards acidic dyestuffs should be desirablyassociated with features of tinctorial uniformity, without jeopardizingthe other physico-chemical specifications of the textile materialconcerned.

With the term polyamides it is intended to connote, as the presentdisclosure proceeds, those polyamides which are generally known in thetrade under the name of nylon accompanied by a numeral indicating theirspecific chemical nature, such as nylon 66, nylon 6, nylon 11.

It is known in the appertaining art that the characteristics ofdyeability of synthetic textile fibres, more particularly polyamides, isa function of the existence and the properties of end groupings of thepolymeric chains. More particularly, the dyeability by acidic dyestuffsis a function of the existence and the number of end amino groupings ofthe polymer. The number of said end amino groupings is generallyexpressed in terms of equivalent amino groupings per 10 grams ofpolymer. The magnitude of said number is a critical factor, which is anindication of the degree of affinity towards the dyestuffs. On the otherhand, the achievement of a high number of end amino groupings is notsufficient, in itself, to ensure the obtention of satisfactory results,inasmuch as said achievement should not prejudice the desired value forthe molecular weight: in addition, the end amino groupings shouldexhibit, as, and of themselves, favorable conditions of affinity towardsthe acidic dyestuffs.

It is known that several installations and methods have F 4 3,632,558 CePatented Jan. 4, 1972 been suggested to improve the tinctorialperformances of spinnable polyamides. For example, and more particularlyin the production of nylon 66, in order to introduce into the polyamidesaid amino end groupings, either an excess of the diamine used for thepolymerization is employed, or the proportional amount of thechain-stabilizer used is appropriately adjusted, said chain-stabilizerbeing usually acetic acid. The latter technique is adopted, morespecifically, in the production of nylon 6, wherein the startingmaterial employed is epsilon caprolactam. Acetic acid used as achain-stabilizer also limits the number of the amino end groupings (NHin such a way that the polymer, and thus also threads and yarns obtainedthereby, may possess the. desired number of said groupings.

These conventional methods are, however, conducive to a few shortcomingsand are subject to certain limitations. For example, if in theproduction of nylon 66, an excess of diamine beyond certain criticalvalues, is adopted, detrimental phenomena of polymer decomposition mayoccur. Likewise, an amount of acetic acid other than the critical one inthe production of nylon 6 does not permit the obtention of the desireddegree of stabilization of the polymeric chains. In both cases, thedesired degree of tinctorial evenness and regularity cannot be obtainedin the production of threads and yarns, in spite of the fact that thesemay be suitable for the production of textile materials on account ofother physico-chemical specifications.

It is also known that the adoption has been suggested of additiveshaving basic groupings, more particularly, amino groupings, in theproduction of spinnable polyamides. Said additives are introduced in themonomer, or monomer mixture, or also in the mass, during progress ofpolymerization, so as to impart to the produced poly amides the desirednumber of dyeable amino groupings. Said additives can be used inassociation with a chainstabilizer, such as acetic acid, to impart tothe polymer the desired viscosity: as an alternative, said additives maypossess, in themselves, the property of acting as chainstabilizers.

In practice, as additives of the kind considered above, amines areemployed which have either primary amino groupings, or primary aminicgroupings in association with tertiary amino groupings. The use of saidadditives, however, cannot be regarded as a satisfactory solution of thecharacteristic technical problems of this invention. Compoundscontaining only primary amino groupings as used heretofore, undergodecomposition phenomena, especially when said additives are used inthose considerably high amounts as are necessary for a high degree ofdyeability to be attained. Amines which also possess a tertiary aminogroupings did not afford, in turn, the most desirable results. Accordingto a tentative interpretation of a few adverse features of said amines,it can be said that these features are the result of the fact that thetertiary nitrogen has no hydrogens available to originate hydrogen bondswith the carbonyl grouping of the adjoining polyamide chains.

In addition, a few conventional products or additives lead to theoccurrence of cross-linking phenomena, which should be positivelyavoided in the production of polyamides for textile uses, wherein it isimperative, for the polymer, that it comprises only rigorously linearchains.

Another drawback of the conventional nitrogeneous additives is theirinadequate compatibility with the monomer and, in general, with thestarting materials used in polymerization (water and others), and, also,with the produced polyamides: more particularly a few additives exhibita tendency towards being removed during progress of subsequenttreatments, for example washing.

Another shortcoming of a few conventional additives is their excessiverate of evaporation under polymerization conditions.

With the foregoing considerations in mind, an object of this inventionis an improvement of the above indicated production methods, such as tolead to the manufacture of synthetic textile products of a polyamidicnature, having a high degree of dyeability and a high tinctorialuniformity with acidic dyestuffs, without exhibiting, or, at leastexhibiting in a much lesser degree, the above enumerated and otherlimitations and drawbacks of the conventional art.

More specifically, it is an object of this invention to identify and touse certain particular additives, which are adapted to perform both thefuncton of carriers of dyeable nitrogenous groupings and of stabilizers,said dyeable nitrogenous groupings exhibiting considerable and constantdyeability properties and being stably connected to their relevantpolymeric chains without the additive giving rise to the occurrence ofundesirable cross-linking phenomena or, in any case, of phenomenasusceptible of prejudicing the linear nature of the chains, asspecifically required in the field of the production of yarns andtextile fibres in general.

It is also an object of the invention to identify and exploitnitrogenous additives which, in addition to the above mentioned propertyof imparting to the product the desirable characteristics of uniform andregular dyeability, exhibit a very high compatibility toward thestarting materials and the produced polyamides, and which do notevaporate, or evaporate to a negligible extent only, underpolymerization conditions.

The additives which have been identified as being characteristic for theinvention consist of nitrogenous organic compounds selected from thegroup consisting of nitrogenous compounds having a primary or secondarynitrogen atom, or both, and in the class of betaines; provided that theypossess at least nitrogen atoms and are endowed with high tinctorialproperties in the presence and under the action of acidic dyestulfs,without, however, giving rise to cross-linking phenomena in polyamides,that is to say, that they have the above indicated critical andessential properties to the end of the production of textile fibres andyarns.

The selection among said nitrogenous compounds, which are characteristicfor the invention, is predomi nantly a function of their availabilityand cheapness of production, of economical factors along with specifictechnical requirements. The nitrogenous compounds having a primary orsecondary nitrogen atom (or both) which are endowed with thecharacteristic properties according to the invention are compoundshaving the general formula wherein R stands for one of the followinggrouping:

an aryl radical an alicyclic radical a branched-chain alkyl a mixedalkyl-aryl, or alkyl-alicyclic radical, and

R' stands for one of the following substituents:

hydrogen methyl a carboxyalkyl having from 2 to 11 carbon atoms anaminoalkyl having from 2 to 11 carbon atoms, and which possibly has anacyl grouping attached to the nitrogen atom, said acyl having from 2 to8 carbon atoms. In the latter case, also the secondary nitrogen atoms ofthe compound can be acylated with an acyl having from 2 to 8 carbonatoms.

an acyl containing from 2 to 8 carbon atoms, and in the above formula,when R is either hydrogen or methyl, R is a mixed alkyl-aryl,alkyl-alicyclic or branchedchain alkyl radical, directly bonded to thenitrogen atom by one or more methylene groupings.

Thus, to the ends of the invention, amines can be used in which theradical R is, for example, phenyl, a substituted phenyl, benzyl (amongthe aryl radicals or the mixed alkyl-aryl radicals), or, when R is analicyclic radical, it can be a cyclopentyl, a cyclohexyl (alsosubstituted) and lastly, among the branched-chain alkyl radicals,isopropyl, isobutyl, tripropylmethyl etc. The radical R can be, inaddition to hydrogen and methyl, also a carboxyalkyl such ascarboxyethyl, carboxypropyl, carboxypenthyl, carboxydecyl and othercarboxyalkyls of the linear or branched series, or a mixed carboxyalkyl,such as an aliphaticaryl carboxyalkyl. When R is an aminoalkyl, it canbe amionethyl, aminopropyl, aminohexyl or it can be also a mixedaminoalkyl, containing for example aryl and aliphatic groupings, suchaminooxylol. When R' is an acyl, the nitrogenous compound will be anamide.

It has been ascertained by the applicant that the inventive nitrogenouscompounds having the general formula given above possess a number ofcarbon atoms which is sufficient to impart to said compounds theproperty of not evaporating or of evaporating, at least, to a muchlesser degree, from the reaction mass at the high temperatures requiredfor polymerization. In addition, the nature of the grouping R, which israther bulky, is such as to impart to the compounds involved a goodcompatibility with the starting materials and the produced polyamides aswell.

Other amino compounds of a nature similar to that of the inventivecompounds, by lying beyond the scope of the limitations imposed by theabove formula, have proved not to possess the desirable essentialcharacteristics for the invention. For example, several amino compoundshave been tested as tinctorial additives in the preparation ofpolyamides: among these, laurylamine has shown poor compatibilitycharacteristics toward the polymer, butylamine evaporated to asubstantial degree during polymerization, butyl-propylamine did notimpart to the produced polyamide a suflicient and regular dyeability andhas shown a poor tendency toward being incorporated into the polyamide.

Within the scope of the amino compounds as identified by the invention,it has been found as a result of studies and experiments, that thestructure of the radical R and the radical R has a decisive bearing onthe behavior and the functions of the used amino additive, and also onthe characteristics of the polyamide as produced with the employment ofsaid additives.

For example, by employing an amine wherein the radical R is a mixedradical as described above, united to the nitrogen atom by a chain ofmethylene groupings, preferably a chain of from 1 to 3 methylenes, andthe radical R is hydrogen or a methyl, t-he aminocompound exhibits aparticularly satisfactory compatibility toward the produced polyamide.

A few examples of said compounds are: benzylamine, hexahydro-benzylamineand derivatives of said amines which are substituted in the ring, forexample 4-methylhexahydrobenzylamine, or beta-tripropylethylamine, andalso N-methyl-benzylamine, N-methyl-hexahydrobenzylamine andN-methyl-beta-tripropylethylamine.

Amides can be used with advantages, more particularly acetylamides,derived from the cited primary amines, for example benzylacetamide, 4methyl benzylacetamide, hexahydrobenzylpropionamide, l-phenyl Nacetyl-3- ammopropane,

The above cited primary and secondary amines can be used with advantagealso if they are salified with either organic or inorganic acids, suchas acetic, hydrochloric acid and others.

Results of very high substantial compatibility are correspondinglyobtained by using nitrogeneous compounds in which R consists of a carbonatoms chain terminated by a carboxyl and comprising from 2 to 11 carbonatoms, consistently with the above given definition. A particularlyinteresting case of such a class of nitrogenous compounds is given bythe use of N-isopropyl-epsilon-aminocaproic acid, for whose preparationepsilon-caprolactam can readily be resorted to, said caprolactam beingthe starting monomer for the production of the nylon 6 polyamide in thecurrent practice of the art. Other favorable compounds, encompassedwithin the class considered here, are N-benzyl-epsilon-aminocaproicacid, N-cyclohexylepsilon-aminocaproic acid and Ntolyl-epsilon-aminocaproic acid.

Other favorable compounds are, for example, N-benzyl-gamma-amino-butyricacid, N cyclohexyl gammaaminobutyric acid, N-isobutyl-gamma aminobutyricacid: among the compounds which can be obtained by using as one of thestarting material omega-amino-undecanoic acid, a monomer used in theproduction of the so-called nylon 11, N-'cyclohexyl-omega-amino-undecanoic acid can be cited. Among thecompounds in which the radical R consists of an aminoalky'l, that is achain of from 2 to 11 carbon atoms, and terminated by a primary aminogrouping, the following can be enumerated:

1hexahydroxylenamino-3propane These compounds are thus diamines whichcontain both a primary and a secondary amino groupings. It has beenascertained that they permit to prepare a polymer having a particularlyhigh dyeability. By using these secondary-primary amino compounds it hasproven to be experimentally practicable to produce polyamides having upto 50-100 dyeable amino groupings, expressed in terms of equivalentgroupings per 10 gms. of polymer, that is, values which correspond to aparticularly high degree of dyeability of polyamides and yarns obtainedthereby.

Also these above listed amino compounds can be used as such, or alsosalified with either organic or inorganic acids such as acetic,hydrochloric acid and others: also the amides derived from saidprimary-secondary diamines can be used with advantage.

The nitrogenous compounds which are characteristic for the invention,but belong to the betaine class, are defined by the following generalformula:

and respond to the conditions that R; s a carbon chain,

provided it contains from 1 to 10 carbon atoms and that R R and R arealkyls, aryls or an alicyclic radical, either substituted orunsubstituted.

For example, among the betaines in which said radical R R and R are anaryl or an alkyl, the following can be listed. phenyldimethylbetaine,phenyldipropylbetaine, triethylbetaine, N-trimethyl-gamma-aminobutyricacid. An example of a betaine wherein R R and R are alicyclic and alkylradicals is cyclohexyldipropylbetaine.

Particularly advantageous results are obtained with the use of betaines,corresponding to the above indicated conditions, and in which saidradicals R R and R are alkyls and more particularly alkyls having from 2to 8 carbon atoms, and R is a saturated linear chain, such asN-triethyl-beta-aminopropionic acid, N-tripropyl-epsilonaminocaproicacid and N-triethyl omega aminoundecanoic acid. Among these betaines,those in which R, contains a carbon atom have proven to be advantageousand easy to prepare, such as triethylbetaine, and tripropylbetaine.

Also the betaines corresponding to the definitions given above can beused either as such or salified.

The inventive additives should be used in a proportion between 0.05 and2, and preferably between 0.2 and 0.6 mole per moles of the usedmonomer.

They are used with possible other additives, such as delustering agents,by adding them to the monomers or monomer solutions at the outset of thepolymerization operations which are carried out to produce thepolyamides. They can also be added during progress of polymerization,provided that the relative viscosity of the reaction mass has notexceeded the value of 2.3.

Their use does not involve any particular modification in the usualpolymerization process run. The invention will be further illustratedwith the aid of the following practical examples Which should not beconstrued as limitations in the operative details of the invention.

EXAMPLES The following Examples 1, 2 and 3 have been obtained with thefollowing procedure: 100 grams of caprolactam and 3 mls. of water alongwith 3 grams of epsilon-aminocaproic acid (catalyst) and the stabilizerto be examined are charged into large glass test tubes forpolymerization. The test tubes are then placed to polymerize in groupsof four or eight at a time in a single heating block having the cavitiesfilled with silicone oil and such as not to induce temperaturevariations Wider than 0.25 C. at 265 C.

On completion of polymerization under atmospherical pressures, thepolymers are placed in a vacuo, as indicated from time to time, forthree hours.

Upon cooling, the polymers are washed, dried and subjected to titrationof the amino groupings with N/ 20 H=Cl solutions. The operation iscarried out in such a way that the titration error is wholly negligible.

EXAMPLE 1 Comparison between methyl-benzylamine acetate and acetic acidAcetic acid is 0.16 gram per 100 grams of caprolactam.Methyl-benzylamine acetate is 0.300 gram per 100 grams caprolactam, thatwhich corresponds to 0.19 mole per 100 moles of caprolactam. Theoperative conditions are as described above.

All the examples show a considerable and unpredictab le superiority ofmethylbenzylamine acetate, both as regards the number and the regularityof the nitrogenous dyeable groupings as compared with acetic acid.

This fact is still more remarkable in that other acetates ofexperimental amines did not show any superior quality as compared withacetic acid as regards the uniformity of the amino groupings. Forexample, methyl-cyclohexylamine acetate and laurylamine acetate were notbetter than acetic acid.

H NH

Methylbenzylamine acetate Acetic acid Equiv. Equiv. E A methyL aminoDeviaamino Deviabenzylamine Polymerization groups per tion from groupsper tion from acetate temperature 10 grs. of average grs. of average andresidual pressure polymer (A) polymer (A) E A acetic acid (1 260 0., 250mm. Hg" 35. a 0. 5 30. 4 +2. 0 36. 8 +1. 0 28. 7 +0.3 35. 8 0 28. 2 0. 235. 3 -0. 5 26. 3 2. 1 =0. 44

Average 35. 8 28.4 Total 2 2. 0 Z 4. 6

(2) 260 0., 250 mm. Hg 37. 3 +0.05 30.4 +0. 4 37. 3 +0. 05 27.7 2. 3 37.1 0. 29.6 0. 4 0. 30 37. 3 +0.05 32. 5 +2. 5 =0 Average 37. 30. 0 Total2 0. Z 5. 6

(3) 260 0., 340 mm. Hg- 45. 1 0. 52.0 +8. 3

. 0 Average 45. 43. 7 1s. 6 Total 2 0.7 Z 16. 6

(4) 260 0., 200 mm. Hg 36.1 +0.15 30. 4 +2.8

0. 05 Average 35. 27. 6 Tot Z 0. 30 27 5 6 (5) 260 0., 180 mm. Hg. 34. 1--0. 25 30. 4 3

. 19 Average a4. 35 20. 1 2. a Total Z 0. 50 2. 2. 6

(6) 260 0., 230 mm. Hg 35. 8 0. 7 28. 8 2. 3

0. 30 Average 35. 1 31. 3 4. 6

otal E 1. 4 4. 6

Consequently, the improved behaviour is not a general rule, but isspecific for the family of compounds having the general formula reportedabove. From the polymers obtained according to this example, yarns of20/5 deniers have been extruded by spinning with a drawing ratio of1:3.6; from these textile tapes have been obtained, to be used for thedyeability tests.

The tapes have been immersed in a dyeing bath at C. containing Alizarineblue in an amount which was calculated in excess with respect to the onewhich would be normally absorbed by the fibre, that is, the bathcontained 10% of dyeing liquor with respect to the weight of the fibre.The tapes have been kept for two hours in said bath and have beencompared with each other on completion of the conventional washing anddrying operations.

The tapes prepared from polyamides produced with the adoption ofmethylbenzylamine acetate have shown a more uniform and more regularcolor, as compared with those obtained with a polyamide produced withacetic acid only.

EXAMPLE 2 Comparison of the stability of the amino groups in polyamidestabilized with methylbenzylamine acetate vs. polyamides produced withacetic acid, when subjected to equal variations of the residualpressure.

Eight large test tubes are placed in a block: of these, four arestabilized with 0.15 gr. of acetic acid and four with 0.300 gr. ofmethylbenzylamine acetate. Polymerization is carried out down to acertain residual degree of vacuum, for example 410 mm. Hg. Two testtubes with acetic acid are removed, along with two test tubes withmethylbenzylamine acetate. Then polymerization is continued, under ahigher vacuum, for example 200 mm. Hg of residual pressure, on the tworemaining test tubes. The group difference caused by the vacuum areseparately evaluated.

Methylbenzylamlnc Acetic acid acetate Equiv. Equiv.

amino Difierence amino Difference A methyl- Polymerlzatiou tcmpergroupsper of the two groups per of the two benzylamine ature (260 0.) and 10grs. of average 11 grs. of average acetate residual pressure polymervalues (A) polymer values (A) A acetic acid (1a) 410 mm. Hg 43. 8 35. 39 35 46.8 52.4 =0 58 Average 45. 30 9. 35 43.85 16.25 25 (1b) 260 mm. Hg36.1 30. 4 35. 8 24. 8

Average"... 35.95 27. 60

(2a) 430 mm. Hg 53.4 44.4

44 4 49. 9 Average 48. 00 14 55 47.15 18.05 18 05 (2b) mm. Hg 34. 1 30.4 34. 6 27. 8

Average 34. 35 29. 10

Methylbenzylamine acetate shows absolute differences due to ditferentproduction operations, which are equal to 0.60.8 of the differencesencountered in polymer with acetic acid. Said differences become 0.5-0.6if, considered in percentage on the amino groupings present. Thus, thepolyamide flake stabilized with rnethylbenzylamine is also moreresistant to differences due to occasional incorrect productionoperations.

EXAMPLE 3 Comparison of the stability of amino groupings in polyamidesstabilized with methylbenzylamine acetate vs. triethylbetaine Tests arecarried out with the above described methods by employing 0.240 gr.methylbenzylamine acetate or 0.424 gr. triethylbetaine per 100 grs.caprolactam (these correspond to 0.15 mole of methylbenzylamine acetate,and 0.33 mole of triethylbetaine per 100 moles of caprolactam).

Methylbenzylamine acetate Triethylbetaine Equiv. Equtv.

amino Dificrence amino Difierenee Polymerization groupings of the twogroupings of the two temperature and per 10 grs. averages per 10 grs.averages residual pressure of polymer (A) of polymer (A) (1) 260 0., 25036.6 0. 2 39. 2 +0. 35 mm. Hg. 37. +0. 2 38. 0. 35

Average 36. 8 E0. 4 38. 86 E0. 7

(2) 260 0., 250 40.6 +2. 75 40. 4 +2. 58 mm. Hg. 36. 3 -1. 65 36. 1 1.72 37.0 0. 85 37.3 0. 52 37. 5 0. 36 37. 5 0. 32

Average 37. 85 25. 50 37. 82 E5. 14

(3) 260 0. 340 45.4 -0. 65 46.2 0. 1 mm. H 46.7 0. 65 4e. 4 +0,1

Average 46. 05 21. 3 46. 3 E0. 2

As can be seen, triethylbetaine has a behaviour as a stabilizer which isvery akin to that of methylbenzylamine acetate.

Betaines, however, must be complaint with the prerequisites indicated inthe present specification. Thus, for example, trimethylbetaine is not agood stabilizer in that it contains only 5 carbon atoms and not theminimum number of 7 required by the present invention.

EXAMPLE 4 The stabilizers which have been used are:

Test (a):

Benzylamine 4-methylcyclohexylarnine Test (b):

Benzylamine acetate Laurylamine acetate In an aluminum block arepolymerized 100 grs. of caprolactam with 5 grs. water and 3 grs.epsilon-aminocaproic acid and the stabilizer concerned. The temperatureis 265 C. and the final pressure of polymerization is 300 mm. Hg.(residual).

In the test (a) a large test tube is charged with 0.321 gr. benzylamineand another large test tube is charged with 0.340 gr.4-methylcyclohexylamine. In both tests, 0.34 mol of stabilizer per 100mols of caprolactam are used.

The polymer is flaked and then washed and dried, and gives the followingresults.

TEST (a) Equivalent amino groups per 10 grs. of polymer Percentage byweight of Stabilizer h Relative viscosity in H2304 a StabilizerBenzylamine 4'meth ylcyclohexylamine a The relative viscosity data insulphuric acid of this example and of the following are determined on asolution containing 1 gr. of polymer in mls. of solution, at atemperature of 20 C. The concentration of sulphuric acid is 96.5% i0.2%.

'Iitrated in venting outs after polymer with respect to the initiallyused amounts.

Test (b) employs in four large test tubes 0.251 gr. of benzylamineacetate (0.17 mole per 100 moles of caprolactam) and in four additionaltest tubes 0.367 gr. of laurylamine acetate (0.17 mole per 100 moles ofcaprolactam). The analysis of the polymer has given the followingresults:

TEST (b) Equivalent amino groups per 10 grs. of polymer Viscosity 1nsulphuric Stabilizer aci Benzylamine acetate Laurylamine acetate EXAMPLE5 Stabilizers used:

Benzylamine acetylamide Benzylamine acetate In a block of aluminum withfour holes, 4 large glass test tubes are introduced, each test tubebeing charged with 100 grs. of caprolactam, 5 grs. water and 3 grs.epsilon-aminocaproic acid.

In two test tubes there have been introduced, as stabilizers, 0.22 gr.of benzylamine acetylamide, whereas the other two test tubes have 0.25gr. each of benzylamine acetate as a stabilizer. In all of the tests,the stabilizer is in a proportion of 0.17 mole per 100 moles ofcaprolactam. Polymerization is carried out at 265 C. initially for fourhours at ambient pressures in an atmosphere of nitrogen, then for 3hours at a pressure lower than the ambient pressure and ending with aresidual pressure of 250 mm. Hg. The polymer is cooled, flaked andwashed for 12 hours with boiling water.

The examination of the polymer has given the following results:

Equivalent amino groups per 10 grs. of polymer Weight percentf ostabilizer Stabilizer Benzylacetamide Benzylamine acetate *Titrated inventing outs after polymerization with respect to the initially usedamounts.

1 1 EXAMPLE 6 N-benzyl-gamma-aminobutyric acidN-isopropyl-epsilon-aminocaproic acid N-benzyl-omega-aminoundecanoicacid Equivalent Relative amino groups viscosity in per 10 grs. sulphuricStabilizer (acid) of polymer acid N-benzyl-g amma-aminobutyric--. 40. 52. 80 N-isopropyl-epsilon-aminocaproic. 42. 0 2. 70N-benzyl-omega-aminoundecanolc 41. 6 2. 85

The flakes have been spun by extrusion and drawn in five filamentthreads, totalling 20 deniers. The fibres do not show any spinningdefect and show a good dyeability and regularity of dyeing with acidicdyes, i.e. alizarine blue, the dyeing operation being carried out as inExample 1. In addition, the stabilizers exhibit a very low volatilityduring polymerization and have a good compatibility towards the polymer.

EXAMPLE 7 The stabilizers used were:

1-benzylamino-3-aminopropane monoacetate 1- N,N-cyclohexylmethyl-an1ino-3 -aminop ropane monoacetate An autoclave is charged with 128kgs. caprolactam, 0.200 kg. titanium dioxide and 1 kg. water.

As stabilizer there are employed: in a test 89 grs. ofl-(N,N-cyclohexylmethyl) amino 3 aminopropanemonoacetate, in the othertest 86 grs. of l-benzylamino- 3-aminopropane monoacetate.

Both stabilizers are thus used in a proportion of 0.17 mole per 100moles of caprolactam.

Polymerization is carried out at 265 C. while heating during three hoursunder a pressure of 3 atmospheres. The gas is then vented out to ambientpressure and finally a vacuum is applied during three hours untilattaining at the end of the operation a residual pressure of 300 mm. Hg.

The extruded polymer is then flaked and washed during 24 hours inboiling water.

The examination of the polymer has given the following results.

Titrated in polymerization venting outs with respect to initially usedamounts.

These tests are examples of the lesser volatility of primary-secondarydiamines with respect to primary-tertiary diamines having nearly thesame molecular weight, since the secondary amino group has a betteraflinity towards the polymer mass as compared with that of the tertiaryamino group.

12 EXAMPLE 8 l-benzylamino-S-aminopropane1-hexahydroxylenamino-3-aminopropane 1(N,N-cyclohexylmethyl)-amino-3-aminopropane hexamethylenediamine Anautoclave is charged with kgs. caprolactarn, 5 kgs. water and 1 'kg.titanium dioxide, the mass being polymerized as set forth in Example 5.

As stabilizers, there were used in a first test 492 grs. of1-benzylamino-3-aminopropane, in another test 552 grs. of1-hexahydroxylenamino-3-aminopropane, in a further test 510 grs. 1-(N,Ncyclohexylmethyl)amino 3- aminopropane and in the fourth test 342 grs.of hexamethylenediamine. All the stabilizers are present in a proportionof 0.37 mole per 100 moles of caprolactam. The polymer has beenextruded, flaked, washed with water and dried.

The examination of the polymer has given the following results:

a Titrated in polymerization venting outs with respect to initially usedamounts.

The flakes have then been spun by extrusion through an extruder so as toobtain S-filament threads. Said drawn threads (drawing ratio 1:3.6) havean overall denier of 20. Pieces of fabrics made with said yarns havebeen dyed with baths containing the acidic dye Alizarine blue with thesame procedure of Example 1.

Dyeability was intense for all the kinds of yarns. However, the firsttwo stabilizers, primary-secondary diamines, proved to be better.Differently from the primary-tertiary amine, they are less volatile andthe polymer prepared thereby has less defects in spinning than the oneprepared with hexamethylenediamine.

EXAMPLE 9 The stabilizers used were:

N-isopropyl-metaxylylenediamine 1-isobutylamino-6-aminohexane1-isopropylamino-omega-aminoundecane Equivalent Relative amino groupsviscosity in Percent by per 10 grs. of sulphuric weight of Stabilizer(monoacetate) polymer acid. stabilizer N-isopropylmcthoxylene diamine81 1. 05 6. 1 l-isobutylaminofi-aminohexane 78 1. 07 6. 9l-isopropylamino-omega aminoundecane 79 1. 04 2 5 I Titrated inpolymerization venting outs with respect to initially used amounts.

Fibres of 20 denier, 5 filament, obtained with said three polymers, showa great atfinity towards acidic dyestuffs 1 3 on account of the highcontent of aminic groups and have also a good regularity duringspinning.

EXAMPLE l l-(N-N, isobutyl-acetyl) amino-3-N'-acetylaminopropanetriethylbetaine N-trimethyl-gamma-aminobutyric acidN-triethyl-epsilon-aminocaproic acid 10 kgs. caprolactam and 100 grs.titanium dioxide, along with 0.5 kg. water are polymerized according tothe method of Example 4 using as the stabilizer, in one test 47 grs. oftriethylbetaine, in a second test 43 grs. of N-trimethyl-gamma-aminobutyric acid, and in another test 64 grs. of Ntriethyl-epsilon-aminocaproic acid. Said stabilizers are then used in aproportion of 0.33 mole per 100 moles of caprolactam.

The polymer is extruded, washed and examined, the results being thefollowing:

Equivalent Relative amino groups viscosity in per 10 grs. of sulphuricStabilizer polymer acid Triethylbetaine 87. 5 2. 67N-trimethyl-gammaamino-butyric acid 35. 5 2. 70N-triethyl-epsilon'aminocaproic acid 38. 2 2. 68

These three polymers have shown, on extrusion, a very good regularityand afiinity towards acidic dyes.

What is claimed is: 1. The method of producing spinnable saturatedallphatic polycarbonamides having a high regularity and tinctorialaflinity toward acidic dyes comprising polymerizing the polycarbonamideforming reactants thereof, in the presence of an organic nitrogenouscompound having at least seven carbon atoms and selected from the groupconsisting of a betaine having the general formula:

m-fv-nl-c 6 0 a where R R and R are alkyls or aryls, or alicyclicradicals, and R is a carbon chain having 1 to 10 carbon atoms, and of acompound having a primary or a secondary nitrogen atom and having thegeneral formula:

where R is selected from the group consisting of an aryl radical, analicyclic radical, a branched alkyl, a mixed alkyl aryl radical, and analkyl-alicyclic mixed radical, and R is selected from the groupconsisting of hydrogen, methyl, 2. carboxyalkyl having 2 to 11 carbonatoms, an aminoalkyl having 2 to 11 atoms and capable of being acylatedon the nitrogen atom with a hydrocarbonoyl radical containing from 2 to8 carbon atoms, and when R is a hydrogen or a methyl, R is selected fromthe group consisting of a mixed alkyl aryl or alkyl-alicyclic radical,or a branched alkyl, directly bonded to the nitrogen atom by one or moremethylene groups.

2. The method of producing spinnable saturated aliphaticpolycarbonamides according to claim 1, wherein in the formula for thenitrogenous compound R is hydrogen and this compound is selected fromthe group con- 14 sisting of benzylamine, hexahydrobenzylamine,4-methylhexahydrobenzylamine, and beta-tripropylethylamine.

3. The method of producing spinnable saturated aliphaticpolycarbonamides according to claim 1, wherein in the formula for thenitrogenous compound R is a methyl radical and the nitrogenous compoundis selected from the group consisting of N-methylbenzylarnine,N-methylhexahydrobenzylamine, and N-methylbeta-tripropylethylamine.

4. The method of producing spinnable saturated aliphaticpolycarbonamides according to claim 1 wherein the nitrogenous compoundhas the formula recited and R is a carboxyalkyl and this compound isselected from the group consisting of N-isopropyl-cpsilon-aminocaproicacid, N-benzyl-epsilon-aminocaproic acid,N-cyclohexylepsilon-aminocaproic acid, N-tolyl-epsilon-aminocaproicacid, N-cyclohexyl-gamma-aminobutyric acid, N-isobutylgamma-aminobutyricacid, and N-cyclohexyl-omegaamino-undecanoic acid.

5. The method of producing spinnable saturated aliphaticpolycarbonamides according to claim 1, wherein the nitrogenous compoundhas the formula recited where R is an aminoalkyl and is selected fromthe group consisting of l-benzylamino-3-aminopropane,l-hexahydroxylylamino-3-aminopropane, 1-cyclohexylamino-3-aminopropane,1 isopropyl-4-aminobutane, 1-benzylamino-6- aminohexane, andN-isopropylmet-axylylenediamine.

6. The method of producing spinnable saturated aliphaticpolycarbonamides, having between 30 and amino groups for 10 grams ofpolymer, and having a high regularity and tinctorial aflinity towardsacidic dyes, comprising polymerizing the polycarbonamide formingreactants thereof, in the presence' of an organic nitrogenous compoundhaving at least seven carbon atoms, said compound being selected fromthe group consisting of nitrogenous compounds having the generalformula:

wherein R R and R are alkyls or aryls, or alicyclic radicals, and R is acarbon chain comprising from 1 to 10 carbon atoms.

7. The method of producing spinnable saturated aliphaticpolycarbonamides according to claim 6, wherein said nitrogenous compoundis selected from the group consisting of triethylbetaine andtripropylbetaine.

8. The method of producing spinnable saturated aliphaticpolycarbonamides according to claim 6, wherein R R and R are alkylshaving 2 to 8 carbon atoms and R is a saturated linear chain, and thenitrogenous compound is selected from the group consisting ofN-triethylbeta-aminopropionic acid, N-tripropyl-epsilon-aminocaproicacid, and N-triethyl-omega-aminoundecanoic acid.

9. The method of producing spinnable saturated aliphaticpolycarbonamides having a high regularity and tinctorial aflinity towardacidic dyes comprising polymerizing the polycarbonamide formingreactants thereof, in the presence of an organic nitrogenous compoundselected from the group consisting of a betaine having the generalformula where R R and R are alkyls or aryls or alicyclic radicals and Ris a carbon chain comprising 1 to 10 carbon atoms, and of a compoundhaving the general formula where R is one of the group consisting of anaryl radical, an alicyclic radical, a branched alkyl, a mixed alkyl-arylradical and an alkyl-alicyclic mixed radical, and R is a hydrocarbonoylradical containing from 2 to 8 carbon 15 atoms and said nitrogenouscompound is employed in an amount between 0.05 and 2 moles per 100 molesof the monomer used.

10. The method of producing spinnable saturated aliphaticpolycarbonamides, having between 30 and 85 amino groups for 10 grams ofpolymer and having a high regularity and tinctorial afiinity towardsacidic dyes, comprising polymerizing the polycarbonamide formingreactants thereof in the present of and in the proportion of between0.05 and 2 moles of additive per 100 moles of monomer, an organicnitrogenous compound comprising at least seven carbon atoms, andselected from the group consisting of nitrogenous compounds having aprimary or a secondary nitrogen atom, or both, and the general formulawhere R is selected from the group consisting of a carbocyclic aromaticradical, an alicyclic radical, a branched alkyl, a mixedalkyl-carbocyclic-aromatic radical or an alkyl-alicyclic mixed radical,and R is a hydrocarbonoyl radical containing 2 to 8 carbon atoms.

1 6 References Cited UNITED STATES PATENTS 2,359,833 10/1944 Faris 260782,359,867 10/1944 Martin 26078 2,585,199 2/1952 Watson 26078 2,765,29410/1956 England 26078 2,834,758 5/ 1958 Shacklett 260-78 2,907,754 10/1959 Howlett et al 26078 3,065,207 11/1962 Andres 26078 3,296,214 1/1967Pickett 26078 3,296,215 '1/1967 Crovatt 26078 3,304,289 2/ 1967Ballentine et a1. 260-78 3,310,534 3/1967 Brignac et al. 260-783,057,830 10/1962 Corbin 26078 3,359,227 12/1967 Amann et al 260783,513,135 5/1970 Hermann et a1. 26078 HAROLD D. ANDERSON, PrimaryExaminer U.S. Cl. X.R.

8-55; 57-140 R; 26078 A, 78 L

